A 49-year-old patient with a genetic expression of BRCA1, was admitted for a bilateral mastectomy and immediate reconstruction with tissue expander, following left breast malignancy (post-lumpectomy and radiation in the same breast). After the operation there were signs of infection in the left breast, for which she was treated with antibiotics. A few days later, mild neurological signs appeared, which resulted in an extensive investigation, and the next day a seizure occurred. Concurrent with the onset of clinical signs, thrombocytopenia and anemia appeared, accompanied by cell fractures in peripheral blood surface and decreased ADAMTS13 activity. The combination of the signs and symptoms led to the diagnosis of thrombotic thrombocytopenic purpura (TTP), probably caused by the antibiotic treatment, and the patient began treatment with plasma-parasites and steroids with a resolution of the findings. It is important to be aware of this entity, because of the disastrous consequences of misdiagnosis and therapeutic failure.